http://www.xfilestimeline.net/XFilesIntroduction.htm
"Although there is no direct connection between the two shows, the series
Fringe connects
The X-Files to
Twin Peaks, putting all three in the same universe.
Fringe not only mentions a promising FBI agent named Mulder, who went off the rails, but features Doctor Jacoby's two-color glasses and says "they were sent to be by a Doctor Jacoby from Washington State." - this refers to the twins peak and x-files connection.
"It was in this Baltimore based television series that actor Richard Belzer's famous character Detective John Munch was first seen. He appears in
The X-Files, Season 5 episode "
Unusual Suspects"), which from a chronological perspective, takes place in 1989, a few years prior to
Homicide: Life on the Street. The Munch character went on cross over into numerous television shows. While some could be considered parodies (e.g.,
Arrested Development), others are serious." - This refers to Homicide and X-files connection... and you know to what homicides connect too, right? LAW & Order.
"Fringe is a sci-fi series that deals with parallel dimensions. In Season 2, episode 1's "A New Day in the Old Town," Senator James Van Horn's remarks suggest that this series takes place in the same universe as
The X-Files. Not only is the X-Files referred to, but FBI agent Mulder is specifically referenced as having gone off the rails. The appearance of the X-Files episode "Dreamland" on television would seem to argue that
The X-Files is a TV show in that universe, however, "Hollywood AD" showed that the adventures of Mulder and Scully had been turned into a movie. It's not known if that movie was later aired on TV (and that's what's being seen on television) or was spun off into a television series. It's also possible that in one universe, the X-Files is a television series, while in another it's history." - this refers to the fringe and x-files connection.
"This episode of Picket Fences was written and intended to be a crossover with the X-Files, picking up where the events of 2x10: Red Museum left off. Although CBS nixed the idea at the last minute, direct references to "Red Museum" remain in the episode." - this refers to the connection between picket fences and X-X-Files.
